Tool holders



Nov. 27, 1956 v. s.'JAM1LKowsK1 Erm. 2,772,094

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TOOL. HOLDERS Filed Jan. 19, 1954 MMQINQMQNIQ.

Z2 llaa United States Patent Toor. HoLDERs Vincent S. Jamilkowski, EastHartford, and Bror Walter Swanson, West Hartford, Conn.

Application January 19, 1954, Serial No. 404,862 r2 Claims. (Cl. 279-16)This invention relates to tool holders, and more particularly to a toolholder having novel features of construction. Y

Many of the difficulties encountered in production tapping and threadingon automatic machinery are traceable to misalignment between the workspindle and the tool holder, and to poor functioning of the holder. Theholder of the present invention is designed to provide a high degree ofaccuracy of alignment between the work spindle and the holder. It alsoprovides frictionless axial movement of its tool holding member as thetool enters into the work piece. The holder of the present invention ispositive in action, is non-sticking, and is more simply and economicallyconstructed than those of the prior art.

Still other objects and advantages of our invention will be apparentfrom the specification.

The features of novelty which we believe to be characteristic of ourinvention are set forth herein and will best be understood, both as totheir fundamental principles and as to their particular embodiments, byreference to the specification and accompanying drawings, in which:

Figure 1 is an elevation of the tool holder of the present invention;

Fig. 2 is a vertical central cross section of the tool holder taken online 2 2 of F ig. l;

Fig. 3 is a section view taken on line 3-3 of Fig. 2;

Fig. 4 is a greatly enlarged section view taken on line 4-4 of Fig. 2;

Fig. 5 is a view taken online 5-5 of Fig. l;

Fig. 6 is a broken away vertical central cross section of anotherembodiment of the tool holder of the present invention; and

Fig. 7 is a section view taken on line 7-7 of Fig. 6.

Referring now to the drawings in detail, the tap holder of the presentinvention comprises a cylindrical housing 11 having an upper or rearwardshank portion 12 of reduced diameter which is adapted to t into theturret of a screw machine, the chuck of a lathe, drill press, or thelike.

A chuck body 13 is mounted at the forward end of tap holder 11, body 13having a shank 14 extending longitudinally into the central aperture 15of the tap holder 11. An annular shoulder on the rearward face of chuckbody 13 abuts the forward face of housing 11.

At the forward end of housing 11 and on the internal periphery thereof,there is an annular groove which accommodates resilient ring 16. A closesliding fit is provided between the internal diameter of ring 16 and theexternal periphery of shank 14, thereby providing an effective Seal toprevent dirt, chips, and oil from entering the inside of housing 11.Ring 16 may be made of any suitable resilient material such as rubber,neoprene, or other suitable material.

' Positioned substantially intermediate the ends of the tool holder, andbetween shank 14 and housing 11, is a substantially cylindrical ballcage 17. Mounted in ball cage 17 and rotating freely therein are aplurality of balls 18 Whose surfaces engage the outer periphery 19 ofshank 2,772,094 Patented Nov. 27, 1956 14 and the internal periphery 21of housing 11. As shown in Fig. 3, balls 1S are spaced through atransverse arc of more than around shank 14 and serve to maintain shank14 substantially centralized relative to housing 11.

On one side of shank 14 there is provided a longitudinal groove 22opposite which there is provided a corresponding longitudinal groove 23on the internal periphery 21 of housing 11. Mounted in ball cage 17 andpositioned in the space between grooves 22 and 23 are a plurality ofballs 24 having a somewhat larger diameter than balls 13. Ball cage 17and balls 1S and 24 provide for the frictionless and free longitudinalmovement of shank 14 within housing 11. At the same time balls 24cooperating with grooves 22 and 23 provide a key arrangement to preventrotational movement of shank 14 relative to housing 1l.

Balls 24 constitute a frictionless rolling key while the perforatedtubular ball cage 17 floats in the space between shank 14 and tap holderhousing 11 and serves to keep balls 18 and 24 spaced apart. The rearwardend of housing 11 is enclosed by a threaded cap 25.

Mounted on the rearward end of shank 14 is a ring 26 maintained inposition thereon by screw 27, a recess 2S being provided in cap 25 toaccommodate the head of screw 27. Ring 26, whose diameter is somewhatgreater than the diameter of shank 14, is spaced slightly apart from theinternal face of cap 25. A coiled spring 29 is mounted around shank 14,one end of said spring abutting against ring 26 and the other end ofsaid spring urging against ring 31 which abuts shoulder 32 on theinternal periphery of shank 12, the internal diameter of said ring beingsmaller than that of aperture 15 to provide a stop for spring 29. Theaction of Aspring 29 normally urges shaft 14 rearward into housing 11.

The forward end of chuck body 13 has an internal aperture 34 which isadapted to accommodate a removable chuck 35 closely tting therein. Chuck35 is fastened into chuck body 13 by means of screw 36 (see Figs. 2 and5) threaded through an aperture in the side of chuck body 13, the bottomend of said screw being adapted to impinge against the outer peripheryof chuck 35 to clamp it securely in position.

The forward portion of chuck 35 extends beyond the forward end of chuckbody 13 and widens out into a flange 33. The rearward surface of flange38 is separated from the forward surface of chuck body 13 by means of acollar portion 39, said separation providing convenient means for theinsertion of a suitable tool for removing chuck 35 from chuck body 13.

A longitudinal axial aperture 41 is provided in chuck 35 to accommodateshank 42 of a threading tap or tool. Shank 42 is maintained in positionin chuck 35 by means of screw 44 threaded through the side of chuck body13, a side hole 45 being provided in chuck 35 for the free movement ofsaid screw.

It will be noted that chuck 35 is an expendable piece since it is madeup specially for each tapping set-up when such work is on a massproduction basis. In order to insure that longitudinal axial aperture 41is in perfect alignment for the tapping set-up where the threadedportion 43 of the tap is to enter into Work piece 46 in perfectalignment, a chuck 35 having no axial aperture is inserted into chuckbody 13 and clamped therein by means of screw 36. With tap holder shankportion 12 inserted into the turret of a screw machine, the tailstock ofa lathe, or the like, a tool in the head stock of the machine isarranged to bore axial aperture 41 in chuck 35, said tool being in theexact position with which the tapping hole will later be aligned for thetap 42. Thus, aperture 41 is drilled and reamed in such t i I Y' 3manner. that the. tapthat. is sitioned in perfect alignment to performits work on Vwork piece 46. Y

In order to provide opportunity for the drill and'i'earn-` i er to boreand smooth aperture 41 for itswhole length, there is provided in` shank14 a central longitudinal re-L cess ,47, said recessbeingl'somewhatwider than hole 41.

insertedtherein will be pothat is to be drilledand reamed in chuck 35.Thus, am-A Y 'ple clearance is provided Vfor the drill and reamer topenetrate through and beyond chuck 35,V and also to provide a space intowhich the shanlootl the tap may extend. After hole 41 has been suitablydrilled andV reamed, 'chuck 35V may remain in position, crit; may bevremovedY to clean out the chips and dirt in recess47, relinserted intochuck body V13 and clampedjin position by'. means of screw 36.YThereafter, the shank of tap 42 may be insertedrinto chuck 35- andclamped in position therein by means of screw 44. Y

When a particular'chuck 35 has served itstp'urpose,v Y

it may be discarded and'a new chuck 35 may be prepared by the foregoingmethod for a subsequent tapping job. 'Y i i 1 YIn operation,the'threadedV portion` 43V of tap 42V is tionless` movement of shank 14`within housing 11, while balls V24 act as a'frictionless key in grooves22 and 23 to prevent the rotation of shank 14, consequently preventingthe rotation of tapV 42. `RingV 16V is suciently yieldable to provide asmooth sliding tit between itself Vand the outer periphery ofjshank 14without providing any appreciable resistance against thelongitudinalmovel ment of the shank` Y' l i Y After the hole has beentapped, the work' piece Vis` reversed introtation and tap 42V withdrawsundelfthe ac- Ytion of spring-29 urging againstY ring 26, therebypulling shank V14 of chuck head 13 back into housing '11'.

'Y i The outward and inward movement of shank 14 is sub-V stantiallyfrictinless and-provides for smoothV operai tion of the tap'in its Workwhile at VVthe same time theV 'key Vballs 24 maintainY theYtapY'alignedAi/vith tap `'housing 11,7 thereby ensuring accuracy of.theftapping function:

Since thethreadin d es engaged in the'sam@ .fris-5 tionless bearingball'mounting as described above for the tapping Vdevice for cuttinginside threads,.it is apparent that the same advantages will accrue toprovider, rsuperior operation for cuttingoutside threads on work pieces.

In this specication, weu-havelexplained the principles of `ourinvention,gand therbest modejin'which we have y contemplated applyingVthose principles, so as lto fdistin-` Vguish our invention fromY otherinventions; and-wehave H particularly pointed outand-'distinctly'claimed Ythe part,

mode or combination whielrweclaimr as our YinventionV or discovery.

While we have slownv and'des'cribed certain preferredYY embodiments ofour invention, it will be understood that Y t modicationsand changes maybe made withoutrdepar't- Y ing from the function and scope thereof, Yasi will be 'Y clear to those skilled in the art. t

We claimz' 1. A tool holderl comprising a housing, Vajehuck bodyV lmovable longitudinally within Vsaid housing, a tubular;

ball cage positioned between said housing and said'rlulckV body,saidtcage being movable longitudinally relative to' either and to `bothsaid housing and said'chuck body, a rst plurality` of balls of asubstantially uniformsize mounted iny said ball cageY and postioned'toroll simultaneously on ftheinner periphery of said housing-and on; theouter peripheryl of said; chuck body,tsaid rst balls'.`

being `,arrayed through a transverse arcY of'more than 180, alongitudinal groove `in the inner; periphery ofV Y said housing, alongitudinal V'groove in'the outer. periphery of said chuckV body andpositioned opposite'said Airstvr mentioned'V groove, a secondV pluralityof lballs Vmloui'nted in said ball cageV and having. a diameter largervthan the'V iirstmentioned` pluralityY of balls, said ksecondplurality'. Y 'Y of balls being movable longitudinally with said ballcage Y W relative to either and toboth said housirigrand said chuckY`bodyysaidv larger diameterI b'alls. engaging both of Vsaid fgrooves forY longitudinal movement only therein,4 said VVlarger diameterVV balls'.preventing the ,rotation ofgsaid Vchuck bodyrelative to saidV housing:-l

2.l A- tool holder comprisingaY housing, Va chuck Vbody 'Y movablelongitudinally within Vsaid housing,V a; tubular The rictionless holderYof thetpresent inventionY may Y alsobe adapted for die threading'asillustrated in Figs.

6 and 7. There kis inserted into VVthe internal'ap'erture of ,chuckbody'l'the shank of an adapter 51 having a 51. is xed in position byscrew 53 threadably inserted 'through ,the wall offchuck body 13, in thesame man;

ner as chuck 35 is fixed in position by screw 36 in Figs. Zand S. Y

'The forwardV portion. of adapter 51 Yextends beyond the forward end. ofchuck body Y13V and widens out into an annular angef54: The rearwardsurface4 ofange 54 is {separatedfrom the` forward surface ofchuck bodyY13 by means of a collar portion' 55, said separation pro- .vidingconvenient means forthe insertion of a tool for f removingadapter51-from chuck bodyv 13'.

4Aperture V56v withinfange 54V accommodatesfa'split ring4 threading die57` secured imposition-V by' adjusting Y andY binding.V screws. 58-extending threadabl-y throughY Vthrough ilange-54. Die 57 -hasa centralaperture 579 axiallyy alignediwith apertures ,52Vand'47, andthe walls610i which constitute a diefor cuttingV threads "ony various; Work.pieces.

jheendsof s nlitiingiy S1-arelr0imded at theperiphery thereof, wherebythey: arej engaged; by thewedgefshaped Y rinse 62 otlspreadiingSerewzfthereby.provdngfmeans i for adjusting the diameter ofthreadedfaperture 59. Y

. central Vaperture'SZ aligned with aperture 47.` YAdapter v ball cagepositioned betweensaid chuck body'and said housing and movablelongitudinally. therebetween, a plurality'i` of;V balls iin said cageuan'dfmox'ra'ble"therewith,V said Y balls being arrayed through aYtra'nsx'ferse arc' ofrmorethan to maintainsaid chuckVbodygsubst'antially een t-rlalize'd` relative t'orsaid housing,alongitudinalgroove in the inner' periphery lof saidhousing,alongitudinalgroove 1 in-the outer periphery of said chuck bodyandpos'itioned' opposite said rst mentionedlgroo'vava second: pluralityof ballsf ofY larger diameter than said'rstY mentioned balls,

said'larger balls being mounted in said cage and aligned.

therein to coact with and move longitudinally vonly with# in' both saidgrooves andv togetherY with the longitudinal movement of said,v cage,said larger ballsfpreventingthe rotationof said chuek'body relative Vtosaidhousing.

Y References Cited inrthe'filev'ofV thispatent UNiTEDLsTATEs PATENTS'389,627Y t Italy 1 Dee; Vto, Y19216

